Joseph Gatt is a British actor that has been cast in Season 4. He may be playing Styr, the Magnor (lord) of the Thenn people, one of the wildling clans.

Gatt is perhaps best known as the motion capture performer and likeness for "Kratos" from the acclaimed God of War video game franchise. He appeared as the Frost Giant, Grundroth in Thor, and Starfleet Science Officer 0718 in Star Trek Into Darkness.

Gatt has a condition called alopecia universalis which made all of his hair fall out at the age of 14.